Method of operation for motor driven vehicles with turbo-transmissions



July 26,1938; i

o. H. HACKER ET A1. METHOD OF OPERATION FOR MOTR DRIVEN VEHICLES WITH TURBO-TRANSMISSIONS Fired July 9, 1934 fr Afr Patented Julv 2s. 1938 vUNITEDsT-Arias PATENT' ori-ICE Mn'rnon oF OPERATION lFoa Mo'roa nmvEN VEHICLES wl'rn- Tonno-'rms- MISSIONS on-the-Brenz,

Germ composed of Waltherand Hanns voith.

any, 'a copartn voith, Hermann ership voith.

Application July 9, 1934, Serial No. 734,3991y In Germany July 10, 1933 1Claim.

Y. The invention relates to a method of operating vehicles with forward and reverse drive equipped with hydrodynamic turbo-transmissions. These hydrodynamic transmissions are characterized by the fact, that when they are engaged, i. e. when their working liquid circuit is lled the motor is mechanically independent ofthe drive element connected to drive-axle or drivewheels. For instance it is possible to let such a vehicle roll backwards while the motor is running in forward direction, for this purpose it is only necessary to reduce thel motor speed to such a speed that the torque developed by the hydrodynamic transmission is not suiilcient to overcoma the force moving the vehicle backwards. `It is furthermore possible to manuvre .with the hydrodynamic transmission in such a way by increasing the motor speed that the torque increasessteadily so that the vehicle is brought smoothly and without any shock to a motionin forward direction.

A vehicle equipped with a hydrodynamic transmission when running up a grade can, therefore, be' stopped by only reducing the motor speed accordingly and can be kept stopped without apply- Iing the brakes by adjusting lthe motor speed so that the vehicle will be maintained in this state for any`length of time land it can be started again by simply accelerating the motor speed. When running downhill it is possible to check the speed ofthe vehicle without lany aid of the brakes by simply engaging the reversegear. Then the secondary partof the hydrodynamic transmission is driven'through the 'reversing gear from the drive 'wheels in reversed direction,l the primary part is driven forward by the engine and the speed of the latter is so adjusted that the desired maximum speed of the vehicle is not exceeded.

Our invention is illustrated by way of example in the accompanying drawing, wherein similar characters of reference indicate corresponding parts throughout the several views, and in which:

mission and reversing gear;

Fig. 3 is a top plan view of one unit; and Fig. 4 is a broken elevation and section of the hydrodynamic turbo transmission.

The invention relates to the equipment of a vehicle and to the method of operation of the trans- (ci. sc-97) same whereby the characteristics, mentioned before, are made use of.A

With more particular reference to the accompanying drawing, and iirst to Figs. 1 and 3, our invention for purposes of illustration is shown in connection with a vehicle I0, having wheels II. The source of power may consist of any suitable engine or motor I3 arranged with its shaft Il extending longitudinally of the vehicle and coaxial with a separate shaft I5 which is to be driven.

vAssociated with the shaft I5 4for operation thereby is a reversing gear transmission means which is denoted as a whole by the reference numeral I6. This reversing gear is suitably geared with the vehicle driving axle Il to cause movement or travel of the vehicle, either in .a forward or backward direction, accordingly as the reversing gear itself is shifted or primed for taking power from the driven shaft I5 and transmitting such power to the axle I1 with a forward driving effect cr a backward driving effect. The

speciiic reversing gear transmission means is not important, for many diierent speciiic clutch mechanisms are known or can readily be devised for converting the power of the driven shaft I5 into iorwardor backward propulsion of the vehicle.

The hydrodynamic transmission is indicated generally at I8 and is represented as comprising a iiow coupling I! in combination with a torque changer 2li. Theprimary wheels a and a of the coupling and torque changer respectively are attached to the driving shaft Il; and the secondary y wheels b and-b' of these respective parts are connected together to-provide a common rotary elef ment 2l one end 2I of which is attached to the driven shaft I5.

Working liquid is passed under pressure from tank -22 into the chamber of primary wheel a through suitable passages as 2l. Liquid is discharged from the chamber of this wheel through an outlet opening 24.

To the chamber in the torque changer, liquid is admitted through an opening 25. 'I'he outlet for the discharge of liquid from the torque changer chamber 'is indicated at 26.

By suitable means which may consist of an operating valve 21, liquid maybe shut oil from the torque changer 20 at the same time liquid is permitted to enter the coupling I8, and these operations result'in emptying the torque changer and, illling the coupling whereby slightly to .decrease torque .transmission'by the'torque changer and to slightly increase torque transmission by Y 4 the coupling whichever is in operation. t

s apparatusjwith the driving axle I1 of the veforce.

hicle. Due to thisarrangement the motor may in operation for driving the vehicle in e. forwerd direction while the vehicle itself may be permitted to travel in the opposite or'backward direction. 'y To accomplish this result the notor speed must be reduced te such eiitent that the torque developed by thehydrodynamic transmission will be irisulcient to overcome the opposite torque deve'foped bythe force which causes or tends cause'ba'ckward `travel of the vehicle.

Pgnother advantage of this arrangement is that the travel of the .vehicle may be changed @from a lleckwardY direction to a forward direction in an easy smooth manner and without shock or sudden jolt. 'I'his maneuver canbe accomplished by increasing the motor speedf to an extent suiiicient to overcome the force that causes or tends to cause backward travel of the vehicle.

l With this hydlodynamic transmission, the vei? hicle may be stopped and maintainedV on a grade Vwithout YYYapplying the brakes, by properly adusting the motor speed to the backward rolling The vehicle can again be started up-grade by accelerating the motor speed. It `will vbe vrealized that while thecifehicle is running downgrade, its speed may be checked without the aid of brakes, simply by shifting the reversing gear into reverse. Through this operation the secondary par?l of the hydrodynamic transmission will be driven through the reversing gear from lthe driving axle in` reversed direction, while the primary part is driven forward by the motor, the speed of which is adjusted to permit movement of the vehicle at the rate desired.

rIf a vehicle is equipped with two engines and two hydrodynamic turbo transmissions which by alzarse means of reversing gear can beecoupledto the drive wheels in order to obtain the forward and backward motion the method of operation on a long downhill grade will as follows: ,Y

One engine is set for driving vin forward direction, the other for backward direction. When one engine is used for the forward direction, the other engine which is used for backward direc- 'tion idles so as to be constantly available for braking operation, although if desired this` other engine may be stopped. With the forward engine the vehicle is brought to the desired speed, then this engine is stopped or set to idling while instead of braking the speed is controlled by acfcelerating or decelerating the second engine, as the case may be. If the grade is interrupted by plane er uphill parts, where a speed loss would ,occur, the first engine can be taken for accelerating again. e

Thismethod of operation has the great advantage that the full engine power is available e for braking purposes and that braking is at the e same time very intense but-smooth andthat no YVwear of mechanical parts but only heating of the working liquideof the turbo transmission occurs. The tlrus generated heat can easily be dissipated by cooers of known type. I

If reversing mechanisms engageabie during opera'tionuare provided, it is possible te also use all engines either for driving or' braking;

We claim:

The method of controlling the speed of travel of a land vehicle having at least two pairs of wheels which comprises, applying an elastic and yielding torque to one pair of wheels tending to drive the vehicle in one direction, applying en elastic and yielding torque to the other pair of wheels tending to drive the vehicle in the opposite direction, and controlling the extent of the two elastic and yielding opposing torques wheredecelerate in either direction of motion.

OSKAR H. HACKER. -ERNST SEIBOLD. 

